TEESHWATEE SHELLS OF AUSTRALIA. 313 



and this species, as the t^vo vah^es upon which Grray founded his 

 description are now in the Museum, having been presented by 

 him a few years ago. TTpon one the locality Macquarrie E-iver 

 is written, and upon the other the name is in his own hand- 

 writing. 



152. TJkio multidektatus, Parreyss. 



Unio multidentatus, Parreyss, Philippi, Abhild. vol. ill. p. 46, pi. iii, 

 fig. 4 ; Kuster''s Con.-Cab. pi. sxxvi. fig. 5. 



Far. = Unio fiilmineus, Parreyss, Philippi, I, c, figs. 5-6 ; Kiister, p. 286, 

 pi. xcvi. figs. 2, 3. 



Ifai. Australia (^Parreyss). 



The differences in outline and dentition pointed out by Philippi 

 in the two forms whicb he considered specific are not, I think, 

 more than individual variations. The Museum purchased of 

 Parreyss, in 1841, four specimens labelled U. fiilmineus, which 

 represent both types. The older the shell, the m.ore multidentate 

 becomes the cardinal tooth. 



153. TJnio geatiosijs, Parreyss. 



Unio gratiosus, Parreyss, Philip-pi, Abbild, vol. i. pi. i. fig. 5 ; Xilster's 



Con.-Cab. p. 239, pi. Ixxx. fig. 3. 

 ffab. Australia (^Parreyss). 



This species has a more finely corrugated surface than IT. mul- 

 tidentatus, and is narrow. 



154. Unio semiplicatus, Kiister. 



Unio semiplicatus, Kiister, Con.-Cab. p. 279, pi. xciv. fig. 4. 



Hah. Australia. 



A narrow form with, the posterior end coarsely wrinkled. 



G-enus Mycetopus. 



155. Mtoetopus etjgatus, Soiveriy. 



Mycetopus rugatus, Sowerby, Conchol. Iconica, vol. xvi. fig. 7 ; Smith, 

 Voy. Erebus ^' Terror, pi. iv. fig. 1 ; Clessin, Kiister' s Con.-Cab. 

 p. 205, pi. Ixvii. fig. 3 ; Lea, Synopsis, ed. 4, pp. 90 & 147- 

 Sab. Victoria River, N.Australia {Cajpt. WicJcham, B.N'., and 

 mus. Cuming.^. 



It is very remarkable that Australia and South America should 

 possess species so much alike as ilZ. siliquosus and the above. 



